reorganized files

This commit is contained in:
V. Ferreira
2026-02-26 02:48:25 +01:00
parent 5916d6a525
commit dbb3b21a67
6 changed files with 403 additions and 384 deletions
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#ifndef POISSON_PROBLEM_HPP
#define POISSON_PROBLEM_HPP
#include <fstream>
#include <iostream>
#include <deal.II/base/quadrature_lib.h>
#include <deal.II/base/logstream.h>
#include <deal.II/base/tensor.h>
#include <deal.II/base/utilities.h>
#include <deal.II/base/index_set.h>
#include <deal.II/lac/vector.h>
#include <deal.II/lac/full_matrix.h>
#include <deal.II/lac/sparse_matrix.h>
#include <deal.II/lac/dynamic_sparsity_pattern.h>
#include <deal.II/lac/solver_cg.h>
#include <deal.II/lac/precondition.h>
#include <deal.II/lac/affine_constraints.h>
#include <deal.II/grid/tria.h>
#include <deal.II/grid/grid_generator.h>
#include <deal.II/grid/grid_tools.h>
#include <deal.II/dofs/dof_handler.h>
#include <deal.II/dofs/dof_tools.h>
#include <deal.II/dofs/dof_renumbering.h>
#include <deal.II/fe/fe_q.h>
#include <deal.II/fe/fe_values.h>
#include <deal.II/numerics/data_out.h>
#include <deal.II/numerics/vector_tools.h>
#include "parameters.hpp"
#include "fields.hpp"
using namespace dealii;
// =-=-=-=-= Poisson Solver =-=-=-=-=
template <int dim>
class PoissonProblem
{
public:
PoissonProblem(unsigned int degree, unsigned int Nv);
void run();
void set_Nv(unsigned int new_Nv);
private:
void create_mesh();
void setup_system();
void assemble_system();
void solve();
void output_results() const;
Triangulation<dim> triangulation;
FE_Q<dim> fe;
DoFHandler<dim> dof_handler;
AffineConstraints<double> constraints;
SparsityPattern sparsity_pattern;
SparseMatrix<double> system_matrix;
Vector<double> solution; // phi
Vector<double> system_rhs;
MappingQ<dim> mapping;
unsigned int Nv;
};
template <int dim>
void PoissonProblem<dim>::set_Nv(unsigned int new_Nv)
{
Nv = new_Nv;
}
template <int dim>
PoissonProblem<dim>::PoissonProblem(unsigned int degree, unsigned int Nv)
: fe(degree)
, dof_handler(triangulation)
, mapping(degree)
, Nv(Nv)
{}
// =-=-=-=-= Make Grid =-=-=-=-=
template<int dim>
void PoissonProblem<dim>::create_mesh()
{
GridGenerator::hyper_cube(triangulation,
Parameters::X_DOMAIN_LEFT,
Parameters::X_DOMAIN_RIGHT);
// Make x-dim boundaries periodic
Tensor<1, dim> offset;
std::vector<GridTools::PeriodicFacePair<
typename Triangulation<dim>::cell_iterator>> periodicity_vector;
GridTools::collect_periodic_faces(triangulation,
0,
1,
0,
periodicity_vector,
offset);
triangulation.add_periodicity(periodicity_vector);
triangulation.refine_global(Parameters::GLOBAL_REFINEMENT);
}
template <int dim>
void PoissonProblem<dim>::setup_system()
{
dof_handler.distribute_dofs(fe);
constraints.clear();
DoFTools::make_hanging_node_constraints(dof_handler, constraints);
// 'boundary' condition phi(x_0) = 0
constraints.add_line(0);
constraints.set_inhomogeneity(0, 0.0);
constraints.close();
DynamicSparsityPattern dsp(dof_handler.n_dofs());
DoFTools::make_sparsity_pattern(dof_handler, dsp, constraints);
sparsity_pattern.copy_from(dsp);
system_matrix.reinit(sparsity_pattern);
solution.reinit(dof_handler.n_dofs());
system_rhs.reinit(dof_handler.n_dofs());
}
// =-=-=-=-= E_field = -dPhi/dx =-=-=-=-=
template <int dim>
class ElectricFieldPostprocessor : public DataPostprocessorVector<dim>
{
public:
ElectricFieldPostprocessor()
: DataPostprocessorVector<dim>("electric_field", update_gradients)
{}
virtual void evaluate_scalar_field(
const DataPostprocessorInputs::Scalar<dim> &input_data,
std::vector<Vector<double>> &computed_quantities) const override
{
AssertDimension(input_data.solution_gradients.size(),
computed_quantities.size());
for (unsigned int p = 0; p < input_data.solution_gradients.size(); ++p)
{
AssertDimension(computed_quantities[p].size(), dim);
for (unsigned int d = 0; d < dim; ++d)
computed_quantities[p][d] = -input_data.solution_gradients[p][d];
}
}
};
// =-=-=-=-= Poisson equation solver =-=-=-=-=
template <int dim>
void PoissonProblem<dim>::assemble_system()
{
QGauss<dim> quadrature_formula(fe.degree + 1);
FEValues<dim> fe_values(fe, quadrature_formula,
update_values |
update_gradients |
update_quadrature_points |
update_JxW_values);
const unsigned int dofs_per_cell = fe.n_dofs_per_cell();
const unsigned int n_q_points = quadrature_formula.size();
FullMatrix<double> cell_matrix(dofs_per_cell, dofs_per_cell);
Vector<double> cell_rhs(dofs_per_cell);
std::vector<types::global_dof_index> local_dof_indices(dofs_per_cell);
ChargeDensity<dim> rhs_function(Parameters::EPS, Parameters::WAVE_NR, Nv);
for (const auto &cell : dof_handler.active_cell_iterators())
{
fe_values.reinit(cell);
cell_matrix = 0;
cell_rhs = 0;
for (unsigned int q = 0; q < n_q_points; ++q)
{
const double rho = rhs_function.value(fe_values.quadrature_point(q));
for (unsigned int i = 0; i < dofs_per_cell; ++i)
{
for (unsigned int j = 0; j < dofs_per_cell; ++j)
cell_matrix(i, j) +=
fe_values.shape_grad(i, q) *
fe_values.shape_grad(j, q) *
fe_values.JxW(q);
cell_rhs(i) +=
fe_values.shape_value(i, q) *
rho *
fe_values.JxW(q);
}
}
cell->get_dof_indices(local_dof_indices);
constraints.distribute_local_to_global(cell_matrix,
cell_rhs,
local_dof_indices,
system_matrix,
system_rhs);
}
}
template <int dim>
void PoissonProblem<dim>::solve()
{
SolverControl solver_control(1000, 1e-12);
SolverCG<Vector<double>> solver(solver_control);
PreconditionSSOR<SparseMatrix<double>> preconditioner;
preconditioner.initialize(system_matrix, 1.2);
solver.solve(system_matrix, solution, system_rhs, preconditioner);
constraints.distribute(solution);
}
template <int dim>
void PoissonProblem<dim>::output_results() const
{
// --- extract DoF coordinates ---
std::vector<Point<dim>> support_points(dof_handler.n_dofs());
DoFTools::map_dofs_to_support_points(mapping,
dof_handler,
support_points);
Vector<double> x_coordinate(dof_handler.n_dofs());
for (unsigned int i = 0; i < support_points.size(); ++i)
x_coordinate[i] = support_points[i][0]; // x-component in 1D
//---- Output density ----
ChargeDensity<dim> rho(Parameters::EPS, Parameters::WAVE_NR, Nv);
DataOut<dim> data_out_rho;
data_out_rho.attach_dof_handler(dof_handler);
Vector<double> density(solution.size());
VectorTools::interpolate(dof_handler, rho, density);
data_out_rho.add_data_vector(density, "density");
data_out_rho.add_data_vector(x_coordinate, "x_coordinate");
data_out_rho.build_patches();
std::ofstream out1("density.vtk");
data_out_rho.write_vtk(out1);
//---- Output electric field & potential ----
DataOut<dim> data_out_E;
data_out_E.attach_dof_handler(dof_handler);
ElectricFieldPostprocessor<dim> electric_field;
Vector<double> dummy(solution.size() * dim);
data_out_E.add_data_vector(solution, "potential");
data_out_E.add_data_vector(solution, electric_field);
data_out_E.add_data_vector(x_coordinate, "x_coordinate");
data_out_E.build_patches();
std::ofstream out2("electric_field.vtk");
data_out_E.write_vtk(out2);
}
template <int dim>
void PoissonProblem<dim>::run()
{
create_mesh();
setup_system();
assemble_system();
solve();
output_results();
}
#endif